Valve for rock drills



Dec. 22, 1931. E Y 1,837,735

VALVE FOR ROCK DRILLS Filed Aug. 27, 1950 HIE/ATTORNEY extension or stem H to extend 40 Patented Dec. 22, 1931 UNITED STATES PATENT OFFICE EDWARD F. TERRY, or PHILLIPSBURG, NEW JERSEY, AssIGNon. To inennsonn neivn COMPANY, OF JERSEY CITY,

JERSEY, A CORPORATION OF NEW J'lElRSE-Y" VALVE FOR ROCK DRILLS App1ieation filed August 27, 1930. Serial mymaioa This invention relates to rock drills, but more particularly to a valve for fluid actuated rock drills of the hammer type.

A few of the objects of the invention are to obtain a quick and positive action of the the usual introverted teeth R to act as abutvalve and to assure a heavy blow of the hammer piston against the working implement. Other objects will be in part obvious and in part pointed out hereinafter, and to all of these ends the inventionconsists of the combination of elements, features of construction and arrangement of parts having the general mode of operation substantially as hereinafter described and claimed and illustrated in the accompanying drawings, in which r d Figure 1 is alongitudinal sectional elevation of a rock drill equipped with a valve constructed in accordance with the practice of the invention and showing the valvein position for admitting pressure fluid into the pistonchamberto drive the piston on its working stroke, and y Figure 2 is a similar view showing the valve in position to admit pressure fluid into the opposite end of the piston chamber for returning the piston.

Referring more particularlyto the drawings, A designates generally-somuch of a rock drill as will serve to illustrate the invention and comprises a cylinder B at the rear end of which is arranged a back head C.

Within the cylinder B is a piston chamber D having in this instance a free exhaust port E which is controlled by a hammer piston F reciprocable in the piston chamber D. The hammer piston F may be of a conventionaltype having a head G and a forward slidably through a closure J, as for instance, a front head for delivering blows to a working implement (not shown) but which may extend into the front head J and-be guided thereby in a well known manner.

In'the rear end ofthe cylinder B is an enlarged bore K to receive, among other elements, rotation mechanism comprising in this instance a fluted rifle bar L which extends intothe cylinder to interlock with a rifle nut O threaded into the head G of the the usual head P ber D is effected.

piston F. Therifie bar L is ments for spring'pressed pawls S carried by theheadP. 7' g I The back head C may be secured'to the cylinder 13 in any suitable manner, as for instance, by the usual spring pressed side provided with I i which is arranged within bolts (not shown) andsaid back head in this instanceforms a housing for a throttle valve T having a central chamber, U which jmay be in constant'communication with a source of pressure fluid supply." In the wall of the throttle valve T is a port V which, position of the throttle valve, registers with a passage Win the back headand' leading to" g '70 a-supply reservoir X also in the back head.

VInterposed between the rotation ratchet and the rearv end of the piston chamber for which it .forms aclosure is a valve chest qY comprising an inner or plug member Z and an outer encircling ring member 6. The plug member Z has a bore 0 therethrough to receive the rifle bar L and carries a lateral flange d which seats against a shoulder e at the juncture of the piston chamber D and the bore K. i r

, Immediately rearwardly of the flange d and forming a part of the plug member Z is a boss f which extends into aboreg of the ring member I) for centralizing the members Z and b with respect to each other at their forward extremities. Adjacent the boss 7 and forming a part of the plug member:Z is a reduced portion in and rearwardly thereof and also forming a part of the plug member Z is a portion j ofminimum diameter which extends into a bore 70 in the rear end of the in the open ring memberb to assist in centralizing the I members Z and b with respect to each other. Within the ring member b is a bore which cooperates with the portions h and 7' of the plug member Z to form a valve chambero;

for the reception of a distributing valve p p of the sleeve type whereby. the distribution of pressure fluid to the ends of the piston chamannular groove q 1n The pressure fluid utilized for actuating the piston is conveyed in this instance to an the ring member I) and opening into the'valve chamber 0 near the front end thereof, and from the annular groove lqdeads alsupply assager which 'extendsrearward-ly through the ring member I) and the rotation ratchet Q, to connn-unieate; withsthe supplyreservoir 'Leadin'gflfrom thef'frontl end I of the valve. chamber 0 and extending through the flange d is a rear inlet port 8 which opensintothe sage w leading from the valve chamber- 0w the atmosphereat a 'point rearwardly of the P -M At the front end of the valve p is anexternal lateral flange m which, duringthe reciprocatio'ns of the valve, moves acrossthe groove g.- The front end of -tl1e=flange constitut'esapressure area y 'which overlies'the rear inlet port or-portss so that compression D may act against the'pressure area v to shift the valve rearvvardly and thus open'com formed in the rear endof the piston chamber .munication-between the groove ,9 and the i-n'let passage or passagess. or'rear end of the :iiange 501s apressure'areaz Onthe opposite of smallen area than the pressure areay-and said pressure areasis constantly exposed to rpressure fiu-id' in the groove g, both to assist i.n "throwing the valve and to hold the valve p immovable during the admission'of pressure 'fiuidto the front end ofthe piston chamber D.

Located at the rear end of the valve p is an introverted flange 2 the front end 3 of v which constitutes a'seatingsurface adapted .to' sea't uponashoulder't' at the juncture of athex ortions h and'j of the inner member Z :'to:limit-:thezforward movement of the valve p.

At. the rear end of the'valve p is a seating surface 5 which is adapted to seat againstthe rear end wall ofthevalve'cham'ber 0 to limit itheirearward travelof the valve, The rear surfaceofthe flangeQ is in this instance provifdedwith a sh allow recess 6 into-which pressure flui'd fromtherear portion by "the piston ,rc'haanber'lD may be conveyed by 'afkicker passage-7 in'thecylinder B and the outer mem ber b to assist the pressure fluid constantly 1 actingiagainst'the pressure-area z'for throwsage 7 opens into the piston chamber]? at a *tions illustrated in Figure i t ereby. Pressure move the valve 29 forwardly.

the exhaust point slightly rearwardly of the exhaust port E and like the exhaust port E is also controlled by the piston F.

Preferably a small leak port 8 is formed in the flange 2 to provide an immediate escape for-:a: portion ofthe pressure fluid admitted into-the recess '6 which,- as'will be readily observed,-constitutes an actuating surface. By.

, forming the. port .8 .in'theflangeQ thepressure fluid admitted into the recess .6,

or at' least a portion thereof, may immediately escape throughan atmospheric vent 9 formed in thls instance in the plug member Z' and in the cylindersB and bieing in constant communication with the port 8. The pressure fluid thus escaping through the port 8 maintains the'vent 9 and thus the shoulder =4 free of 'such dust and di rt which might otherwise impede the action-of the valve or cause "it to-short- S stroke. v v

The operation of the device is as follows 'Withthev-alve p and the piston F in the posi- 1' pressure fluid Willa flow from-thegroove- Q through the rear inlet passage orpassages 8 into the rear end ofthepiston chamberD to drive the piston its" working stroke. During 5F forwardly on M such admlsslon cf pressure fluid llltUthB rear end of the piston chamber the pressure fluid will act-against thepressure area y ELIld' Hlitlhtain the valve 20 immovable in itsrearm'ost position} As the piston-F proceeds-forwardthe kicker passage 7- will be uncovered the recess 6 and, together with that-pressure fluid acting against the pressure area a; will This movement of the valve p will take place at about the in- "be exhausted tothe atmosphere, it beingounderstood of course that the pressure Within the recess 6 will have been previously reduced in value due tothe escape of a: portion thereof through the leak-port 8 and the atmospheric vent 9. g i

Upon movement of the valve p to the new position and the simultaneous delivery of the blow of the hammer piston against the'working implement pressure fluidwill flow from the groove 9 acrossthe pressurearea'zagainst which it acts to hold the valve pstationary in the front end of the valve chamber, thence flows through the front inlet passage t to return the piston Fto itsinitial position.

The air compressedin the rearendof the, piston chamber D after the piston F covers port E. andthe kicker-passage 7 fluid will thenfiow-int'o F 's J-ant't'he piston F unccvers the exhaust port 1 will act against the pressure'area y to again v n return the valve to its initial position. I =1ngfih9-VfllV forwardly. The kicker pas- During the-forward stroke of the PlStOIl V ly subjected to live ber D will be forced therefrom through the inlet passage t, the neck 0 in the valve and through the atmospheric passage w, so that during the Working stroke of the piston its movement will not be in any Way retarded by compression which, if unrelieved, would cushion the blow of the hammer piston F.

I claim:

In a fluid actuated rock drill, the combination of a cylinder having a piston chamber and a piston therein, an exhaust port in the cylinder controlled by the piston, a valve chest having a valve chamber and a supply passage, inlet passages leading from the valve chamber to the piston chamber, a valve in the valve chamber having a flange at its front end movable across the supply passage for controlling the flow of pressure fluid to the inlet passages, a pair of opposed differential pressure areas on the flange, the larger of said pressure areas being subjected to compression for throwing the valve into a position to admit pressure fluid into the rear end of the piston chamber and being subsequentpressure fluid for holding the valve in such position, the smaller of said pressure areas being constantly exposed to pressure fluid tending to move the valve to a position for admitting pressure fluid into the front end of the piston chamber and for holding the valve in such position, an introverted flange on the rear end of the valve having front and rear seating surfaces, said rear seating surface constituting an actuating surface intermittently subjected to pressure fluid valved by the piston to assist the pressure fluid acting against the smaller pressure area in throwing the valve, a vent in the valve chest for subjecting the front seating surface to atmospheric pressure, and a passage in the introverted flange to intermittently pass pressure fluid through the vent for preventing the entrance into the vent.

In testimony whereof I have signed this specification.

EDWARD F. TERRY.

of foreign matter 7 

